Method for providing voice-over-IP service

ABSTRACT

A system and method, i.e. Voice Proxy Server (VPS), is invented for managing Voice over IP (VoIP) services between a NAT enabled private network and a public network such as the Internet. The VPS acts like the Call Agent to the nodes in the private network and it represents an embedded voice client to the real Call Agent in the public network. Each logical line of the VPS corresponds to a real voice line in the private node. VoIP signaling messages may be carried in the payload of the IP packets. VPS will properly translate IP address and/or port number information in the payload to correctly route the signaling data between networks. Additionally, VPS will forward the incoming Real Time Protocol (RTP) packets to the real destination in the private network.

TECHNICAL FIELD

The present invention relates to managing network services betweennetworks and in particular to managing voice-over-IP (VoIP) service in aNetwork Address Translation (NAT)-enabled private network environment.

BACKGROUND OF THE INVENTION

Data is transmitted over a network through paths in digital data packetsthat traverse routers in the network to arrive at a desired destinationover IP protocols. Often, data streams must be delivered from a publicnetwork to a local node or device in a private network and vice versa.In these situations, any IP-based services are delivered to or from alocal node or device through an entry or exit point of a local network.This entry/exit point functions as a gateway for data such that thepublic network recognizes a single address for the private network.Typically, Network Address Translation (NAT) is employed to present theprivate network to the Internet or other public network with oneaddress. In this way, the NAT translates individual IP addresses foreach device in the private network for the public network such that theprivate individual IP addresses are concealed from the public network.This results in conservation of addresses and added efficiency of thenetwork interfaces.

Messages or data being transmitted in networks contain a header andpayload. The header is the portion of a message or data that containsinformation that guides the message to the intended destination.Information contained in the header may include the address of thesender, the address of the receiver, precedence level, routinginstructions, etc. Transmitted messages or data further contain apayload portion. The payload portion is in the data portion of the IPpacket. An interface between the private network and the public networkor Internet must know the mapping between a local node or device and itsspecific IP address and User Data Protocol (UDP) port to correctly routedata to the proper destination. The Network Address Translation (NAT) atthe gateway is such an interface. It establishes the said mappingbetween the private and public networks to interpret address data in theIP headers and delivers any incoming data to the desired local node ordevice.

However, VoIP protocols sometimes contain address information in thepayload (i.e., data portion of the IP packet). One example of such aVoIP protocol is MGCP/NCS (Media Gateway ControllerProtocol/Network-based Call Signaling protocol). MGCP/NCS protocol isused for call processing signaling control to provide Voice-over-IP(VoIP) services. In situations where specific IP address informationand/or port number information is contained in the payload, the NAT,which only interprets data in the IP header, is unable to properlytranslate the address information or port number information. As aresult, data is not properly delivered to the desired destination in theprivate network.

Further, the actual voice stream is carried by the Real-Time TransportProtocol (RTP). The IP address and port number information for the RTPpackets are defined by the Session Description Protocol (SDP) includedin the MGCP/NCS payload and need to be translated properly. In addition,the voice stream, i.e., the RTP packets, need to be routed properly tothe intended destination. Therefore, the mapping information isnecessary at the gateway for proper routing of data to the correct finaldestination within the private network. The data packet is delivered tothe gateway of the private or local network and the gateway must thenroute the data to the intended destination within the private or localnetwork. The NAT does not have address mapping information and thereforecannot properly route data to the desired destination node.

Therefore, there exists a need in the art to properly translate addressand/or port number information such that VoIP signaling packets aredelivered to the desired destination node within a private or localnetwork and public network.

Further, there exists a need in the art to provide address mappinginformation and actually perform the routing if necessary for deliveryof VoIP voice packets to the desired destination node within a privateor local network and public network.

SUMMARY OF THE INVENTION

In one exemplary embodiment of the present invention, a method isprovided for managing network services between a plurality of networkscomprising receiving an Internet Protocol data packet with acorresponding address from a first network source, wherein the InternetProtocol data packet comprises a header and a payload and the payload ofsaid Internet Protocol data packet contains at least a portion of adestination address; translating the destination address; and deliveringthe Internet Protocol data packet to a destination node on a secondnetwork based on said translating.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary network with a voiceproxy server of the present invention.

FIG. 2 is a block diagram illustrating an exemplary network with thevoice proxy server and call agent.

FIG. 3 is a block diagram illustrating the voice proxy server with amapping table.

FIG. 4 a illustrates message flow of a Restart in Progress (RSIP) in anexemplary embodiment of the present invention.

FIG. 4 b is a flowchart illustrating an exemplary method of RSIP messageflow.

FIG. 4 c is a flowchart illustrating an exemplary method of RSIP messageflow with RestartMethod being “graceful” or “forced” or “disconnected”.

FIG. 5 a illustrates an exemplary embodiment of message flow in clientregistration.

FIG. 5 b is a flowchart illustrating an exemplary method of RSIP messageflow; the voice proxy server 100 receives a RSIP message withEndpointID=“*@VC” and RestartMethod=“restart”.

FIG. 5 c is a flowchart illustrating an exemplary method of RSIP messageflow with RestartMethod—“graceful”, “forced”, or “disconnected”.

FIG. 6 a illustrates an exemplary embodiment of message flow inNotification Request (RQNT).

FIG. 6 b illustrates an exemplary embodiment of message flow inNotification Request (RQNT) wherein EndpointID is a wild card.

FIG. 6 c is a flowchart illustrating an exemplary method of RQNT messageflow with EndpointID and NotifiedEntity specified.

FIG. 7 a illustrates an exemplary embodiment of message flow forNotifications (NTFY).

FIG. 7 b is a flowchart illustrating an exemplary method of NTFY messageflow.

FIG. 8 a illustrates an exemplary embodiment of message flow for CreateConnection (CRCX).

FIG. 8 b is a flowchart illustrating an exemplary method of CRCX messageflow where EndpointID is a single endpoint.

FIG. 9 a illustrates an exemplary embodiment of message flow for CreateConnection (CRCX) where EndpointID is a wild card.

FIG. 9 b is a flowchart illustrating an exemplary method of CRCX messageflow where EndpointID is a wild card.

FIG. 10 a illustrates an exemplary embodiment of message flow for Modifyconnection (MDCX).

FIG. 10 b is a flowchart illustrating an exemplary method of MDCXmessage flow where EndpointID is a single endpoint and NotifiedEntity isspecified.

FIG. 11 a illustrates an exemplary embodiment of message flow for DeleteConnection (DLCX) from a call agent.

FIG. 11 b is a flowchart illustrating an exemplary method of DLCXmessage flow where EndpointID is a single endpoint and Notifiedentity isspecified.

FIG. 12 a illustrates an exemplary embodiment of message flow for DeleteMultiple Connections from a call agent where ConnectionID is notspecified.

FIG. 12 b is a flowchart illustrating an exemplary method of DeleteMultiple Connections message flow.

FIG. 13 a illustrates an exemplary embodiment of message flow for DeleteMultiple connections from a call agent where CallID and ConnectionID arenot specified.

FIG. 13 b is a flowchart illustrating an exemplary method of DeleteMultiple connections message flow.

FIG. 14 a illustrates an exemplary embodiment of message flow for DeleteConnection (DLCX) from a voice client.

FIG. 14 b is a flowchart illustrating an exemplary method of DLCXmessage flow.

FIG. 15 a illustrates an exemplary embodiment of message flow for AuditEndpoints (AUEP).

FIG. 15 b is a flowchart illustrating an exemplary method of AUEPmessage flow.

FIG. 16 a illustrates an exemplary embodiment of message flow for AuditMultiple Endpoints.

FIG. 16 b is a flowchart illustrating an exemplary method of AuditMultiple Endpoints where EndpointID=*@VPS.

FIG. 16 c is a flowchart illustrating an exemplary method of AuditMultiple Endpoints where MaxEndpointIDs are specified.

FIG. 16 d is a flowchart illustrating an exemplary method of AuditMultiple Endpoints where MaxEndpointIDs and SpecificEndpointIDs arespecified.

FIG. 16 e is a flowchart illustrating an exemplary method of AuditMultiple Endpoints where SpecificEndpiontIDs are specified.

FIG. 17 a illustrates an exemplary embodiment of message flow for AuditConnection (AUCX).

FIG. 17 b is a flowchart illustrating an exemplary method of AUCXmessage flow where EndpointID is a single endpoint.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method and system of properly routingdata, such as packets associated with Voice-over-IP (VoIP) servicebetween networks. When data packets are transmitted through a network,specific IP address and/or port number information may be located in thepayload. The NAT can only translate addresses in the IP header and thoseapplications that use IP addresses in the IP payload will break at theNAT environment. Protocols that provide the VoIP service, for example,the Media Gateway Controller Protocol/Network-based Call SignalingProtocol (MGCP/NCS) provide VoIP messages, such as MGCP/NCS messages,that are carried in a UDP/IP message. In other words, the MGCP/NCSmessage is in the payload portion of a UDP/IP message. The MGCP messagecomprises a specific IP address and port number which are in the IPpayload and cannot be translated by the NAT. Therefore, VoIP servicecannot be provided in a NAT-enabled private network. The presentinvention provides a solution to support VoIP service that may co-existwith the NAT and provide a method and system of translating the addressinformation of the message in the header and payload such that the datapacket may be routed properly to the desired destination from a publicnetwork source to a local destination node in a private network and viceversa. Additionally, the invention also supports the routing of theincoming voice packets to the desired destination in the privatenetwork.

In an exemplary embodiment of the present invention, the MGCP/NCSprotocol is used for call processing signaling control to provide VoIPservices. It should be appreciated that the invention is not so limited,as a variety of IP protocols may be used without deviating from thescope or spirit of the present invention. For example, SessionInitiation Protocol (SIP) may also be used and the system and method ofthe present invention may properly translate IP address and/or portnumber information.

MGCP messages are carried in the data portion (payload) of the UDP/IPpackets with the header containing the identifier of the endpoints. An“endpoint” is a network element or component at the end of the network,such as a transmitter or receiver or an originating or terminatingdevice, and may be represented by an endpoint identifying parameter, forexample, an EndpointID. The endpoint identifying parameter comprisesspecific information to identify a particular network element orcomponent. An example of a typical form of an endpoint identifyingparameter, such as an EndpointID of an endpoint, islocal-name@domain-name or an IP address. There are many parameters inthe message header and many of these parameters require specific names,specific IP addresses and/or port numbers which may be all located inthe IP payload.

For proper delivery of data packets to the desired node in a privatenetwork, a gateway may be utilized for receiving the data packets fromthe public network, such as the Internet for example, and routing thedata packets to the desired node in the private network. Within thegateway, a voice proxy server (VPS) operates as the intermediary. Likethe NAT, the VPS establishes an IP address/port mapping table when theVoIP clients in the private network initiate their contacts to the VoIPcall agent in the public network. In addition, the VPS translates anyaddress/port information in the IP payload before relaying the IPpackets to a public network. The VPS then uses mapping information todeliver data packets from the public network to the desired destinationwithin the private network as well as to deliver data packets from anode in a private network to the desired destination in the publicnetwork. For VoIP protocols wherein essential IP address or port numberdata is located in the payload, the VPS may properly translate the datafor routing to the desired destination.

FIG. 1 illustrates an exemplary embodiment of a Voice Proxy Server (VPS)100 of the present invention in relation to the local nodes in a privatenetwork. There may be any number of local nodes in the private networkin connection with the VPS 100. For illustration purposes, FIG. 1 showsthree voice clients (VC) 101, 102, and 103. Each of the local nodes hasa private IP address. The VPS 100 has a globally unique registered IPaddress that is recognized by the public network. It is the access pointfor the private network to the public network, and vice versa. It shouldbe noted that the VPS has twofold functionality. On the one hand, itacts as a “virtual call agent” to the voice clients on the privatenetwork while on the other hand, it behaves as multiple “virtual voiceclients” to the Call Agent 105. These multiple “virtual voice clients”reside on the same address but different ports. This will be illustratedin the exemplary embodiments described herein.

When a call is placed from a local node, for example, a call signalingpath is set up by the call agent (CA) 105. In one example, the calloriginates at the VC 101 and an off-hook signal is received at the VPS100 and relayed to the CA 105. The CA 105 responds through the VPS 100back to the VC 101 with a dial tone. The response from the CA 105 isreturned to the address of the VPS 100, in this example, because thepublic network where the CA 105 resides need only recognize the oneaddress of the VPS 100 rather than each and every local node in theprivate network.

As an example, the user inputs a destination number (e.g., phone number)which is relayed through the VPS 100 to the CA 105, then to the VoIPgateway 104 and to the Public Switched Telephone Network (PSTN) 106.Thus, the CA 105 manages call signaling. In this example, the privatenetwork nodes such as the VC 101, VC 102 or VC 103 each have uniqueprivate addresses and each communicates with the VPS 100. The CA 105need only recognize the globally unique registered address of the VPS100 in the public network. In this way, the VPS 100 acts as an embeddedclient to the CA 105 with several access lines. Each of the access linescorresponds to a real line in a node in the private network, such as theVC 101. At the same time, the VPS 100 acts as a “call agent” to thelocal nodes in the private network since the address of the CA 105 neednot be recognized by the local nodes. Instead, the local nodes need onlyrecognize the address of the VPS 100. In this exemplary embodiment,therefore, the public network need only recognize one address for all ofthe local nodes in a private network which is the address of the VPS100.

As illustrated in this exemplary embodiment, the VPS 100 resides at agateway which is on the edge of a broadband private network andfunctions as an entry/exit point to the public network. IP-basedservices, such as Voice-over-IP (VoIP), can be delivered to a privatenetwork through the VPS 100. VoIP data is received in data packets usingVoIP protocols. One example of a commonly used VoIP protocol is MediaGateway Controller Protocol/Network-based Call Signaling protocol(MGCP/NCS). In such VoIP protocols, specific IP address information orport number information is contained in the payload of the message. TheVPS 100 effectively translates the address or port number information inthe payload of the message to route the data to the desired destinationwithin the private network.

FIG. 2 illustrates a second exemplary embodiment of the presentinvention. The private network as illustrated contains local nodes thatmay be voice clients 101, 102 or 103, for example. It is noted that thelocal nodes are not so limited and may be of any number. Each local nodein the private network communicates with a broadband wireless accesspoint 201 (BWAP). The BWAP 201 contains the VPS 100, which has aglobally unique registered address. The BWAP connects through a cablenetwork 202, for example, to network server 205, which contains the CA105. In this example, data is transmitted through the Cable ModemTermination System (CMTS) 203, Ethernet switch 204 and through a VoIPgateway 104 to the Public Switched Telephone Network (PSTN) 106. Datamay also be sent through routers 207 to the Internet 209. The CA 105manages call signaling and recognizes the address of the VPS 100 in theBWAP 201; however, the CA 105 does not need to recognize each individualunique address of each local node in the private network. The voiceproxy server 100 maps the local node in a private network, for example,to its specific IP address and/or UDP port. Such information isnecessary for effective and accurate delivery of VoIP data packets.

FIG. 3 illustrates an exemplary embodiment of the VPS 100 of the presentinvention. In this example, the VPS 100 contains a mapping table 301 forstoring logical line numbers, actual endpoint identifying parameters,actual private IP address and port number, and all other relatedinformation as illustrated, available logical line numbers or the actualendpoint identifying parameters (EndpointIDs) associated with thelogical line numbers may be stored, for example in a line number field302 and in an EndpointID field 303, respectively.

FIG. 4 a–FIG. 4 c illustrate exemplary applications of the VPS 100 andthe mapping table 301. In an exemplary embodiment illustrated in FIG. 4a and FIG. 4 b, a Restart in Progress (RSIP) message is received at theVPS 100 from a voice client 101 with an endpoint identifying parametersuch as EndpointID and RestartMethod specified (step 401). In oneillustrative embodiment, the RestartMethod=“restart” and, in response toreceiving the RSIP message (step 401), the VPS 100 verifies that theparticular EndpointID exists by referencing a line mapping table (step402). If the corresponding EndpointID is found, then the endpoint IDparameter is replaced with a new identifier (step 404) and the messageor command is delivered to the CA 105 (step 406). If the correspondingEndpointID is not found (step 403), an available line number to thevoice client 101 is stored in the line mapping table with acorresponding endpoint identifying parameter (e.g., EndpointID) suchthat the corresponding line number of the EndpointID may be retrievedfrom the mapping table (step 405). The EndpointID parameter is replacedwith a new identifier (step 404) and the message or command is deliveredto the CA 105 (step 406).

In another illustrative application illustrated in FIG. 4 c, theRestartMethod=“graceful” or “forced” or “disconnected” and, in responseto receiving the RSIP message (step 410), the VPS 100 verifies that theparticular EndpointID exists by referencing the line mapping table (step411). Endpoints that have been recognized and powered up and therefore“exist” may send “graceful”, “forced” or “disconnected” messages.Therefore, if a “graceful”, “forced” or “disconnected” message isreceived and if the corresponding EndpointID is not found, an error mostlikely occurred. In this case, the VPS sends a NACK response back to thevoice client 101. The NACK response is a negative acknowledgementresponse that indicates that the EndpointID is incorrect. Otherwise, theendpoint is identified, a NACK response is not returned and the linenumber of the corresponding EndpointID from the mapping table isretrieved and the EndpointID parameter is replaced with a new identifier(step 413). The RSIP message is then delivered to the CA 105 (step 414).

FIGS. 5 a–5 c illustrate another exemplary application of the VPS 100 ofthe present invention. In this example as illustrated in FIG. 5 a andFIG. 5 b, the VPS 100 receives a RSIP message with EndpointID=“*@VC” andRestartMethod=“restart” (step 501). The VPS 100 returns an ACK and AUEPmessage with EndpointID=“*@VC” querying the number of lines the voiceclient 101 has (step 502). The voice client 101 sends a list ofEndpointIDs to the VPS 100 (step 503) and the VPS 100 accesses the linemapping table to verify whether the EndpointIDs exist (step 504). If theEndpointIDs do not exist, the VPS 100 allocates a logical line number toeach of the endpoints of the voice client 101 (step 505) and saves allline numbers and corresponding EndpointID information in the mappingtable such that the corresponding line number of the EndpointIDs may beretrieved from the mapping table (step 506). The EndpointID parameter isreplaced with a new identifier (i.e., the VPS's ID and line number)(step 508) and the message is delivered to the CA 105 (step 509).

In another illustrative application depicted in FIG. 5 c,RestartMethod=“graceful”, “forced” or “disconnected” and, in response toreceiving the RSIP message from the voice client 101 (step 510), the VPSaccesses the line mapping table to verify that the corresponding voiceclient 101 exists in the line mapping table (step 513). If the addressis not found, an error most likely occurred and the VPS returns a NACKresponse. A NACK response is a negative acknowledgement response thatindicates that an EndpointID is incorrect. Otherwise, the address isfound, the VPS does not return a NACK response and for each endpoint ofthe voice client, the VPS 100 sends a RSIP message with the EndpointIDparameter set to the new identifier to the call agent (step 515). Whenall responses from the call agent are received, the VPS sends an ACKmessage to the voice client (step 516).

FIG. 6 a–FIG. 6 c illustrate another exemplary application of the VPS100 of the present invention. In this example, the VPS 100 receives aNotification Request (RQNT) message from a CA 105 (step 601), the RQNThaving a single EndpointID (FIG. 6 a) or multiple EndpointIDs, e.g., awild card EndpointID (FIG. 6 b). A parameter specifying notificationsuch as a NotifiedEntity parameter may also be specified. In thisexample, the VPS retrieves the local voice client in the case of asingle EndpointID or a plurality of voice clients in the case ofmultiple EndpointIDs or a wild card EndpointID from the line mappingtable according to the EndpointID(s) specified in the RQNT command (step602), saves the NotifiedEntity that is specified in the RQNT command(step 604), replaces the EndpointID parameter(s) with the local voiceclient identifier(s) (step 603) and replaces the NotifiedEntity with theaddress of the VPS (step 605). The RQNT command is then delivered to thedesired local voice client(s) (step 606), which responds back to the VPSwith an ACK (step 607). After the response is received from the voiceclient 101 (or all of the voice clients 101 in the case of multiplevoice clients 101), the VPS may then send the response to the CA 105(step 608).

FIGS. 7 a and 7 b illustrate another exemplary application of the VPS100 of the present invention. In this example, the VPS 100 receives aNotify (NTFY) message from the voice client (step 701). A NotifiedEntityparameter may also be specified. After receiving the NTFY message, theVPS retrieves the logical line number from the line mapping table (step702) according to the EndpointID specified in the NTFY command. TheEndpointID parameter is replaced with a new identifier (i.e.,aaln/LN@VPS) (step 703) and the NotifiedEntity parameter is replacedwith a previously saved identifier (step 704). The NTFY command isdelivered to the restored NotifiedEntity (step 705), which correspondsto the call agent 105. The VPS 100 sends the response received to thevoice client 101 (step 706).

FIG. 8 a and FIG. 8 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS 100 receivesa create connection (CRCX) command from a call agent (step 801) withEndpointID being a single endpoint (e.g., the VPS 100). The CallID andNotifiedEntity may also be specified. After the CRCX command is receivedat the VPS 100, the local voice client 101 is retrieved from the linemapping table based on the specified EndpointID in the CRCX command(step 802). CallID and NotifiedEntity as specified in the CRCX commandare saved (step 803). The EndpointID parameter is then replaced with thelocal voice client identifier (step 804) and the NotifiedEntity isreplaced with the address of the VPS 100 (step 805). The CRCX command isthen delivered to the designated desired local voice client 101 (step806) which returns a response with a descriptive parameter such as aLocalConnectionDescriptor parameter to the VPS 100 (step 807). The VPS100, after receiving the response with the LocalConnectionDescriptorfrom the voice client 101, saves a parameter identifying the connectionsuch as the ConnectionID and saves the IP address and Port numberspecified in the LocalConnectionDescriptor parameter (step 808) (i.e.,private-known media packet receiving address). A port number is assignedwithin the VPS 100 to this connection, this port number and the IPaddress of the VPS 100 being the public-known media packet receivingaddress (step 809). This public to private address mapping informationis stored. Then the modified response with the VPS's IP address and Portnumber (i.e., the public-known address) in the LocalConnectionDescriptoris sent to the restored NotifiedEntity (step 810), which corresponds tothe call agent 105 (step 2 in FIG. 8 a). The VPS then waits to receivethe voice/data packets on the assigned port and forward them to the portof the voice client 101. Alternatively, the NAT (Network AddressTranslation) may be informed of the public to private address mapping toperform proper translation for incoming data packets.

FIG. 9 a and FIG. 9 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS 100 receivesa create connection (CRCX) command from a call agent (step 901) withEndpointID having a wild card, “$”. The CallID and NotifyEntity may alsobe specified. The VPS 100 retrieves any one of the local voice clientsfrom the line mapping table (step 902). The CallID, NotifiedEntity, andTransaction Identifier as specified in the CRCX command are saved (step903). The EndpointID parameter is replaced with the local voice clientidentifier (step 904) and the NotifiedEntity is replaced with its ownaddress (step 905). The CRCX command is then delivered to the localvoice client from the voice proxy server (step 906). Then the voiceclient returns a response with a LocalConnectionDescriptor parameter andTransaction Identifier to the VPS 100 (step 907). The VPS 100 retrievesthe logical line number from its line mapping table based on theTransaction Identifier (step 908). The ConnectionID is saved and the IPaddress and Port number specified in the LocalConnectionDescriptorparameter from the voice client is saved as a private-known media packetreceiving address (step 909). A port number within the VPS is assignedto this connection so that the public-known media packet receivingaddress is the VPS's IP address and port number. This public to privateaddress mapping information is saved (step 910). The modified responsewith VPS IP address, Port number in the LocalConnectionDescriptor andthe VPS logical line number in the SpecificEndPointID is sent to therestored NotifiedEntity (step 911), which corresponds to the call agent105 (step 2 in FIG. 9 a). The VPS then waits to receive the voice/datapackets on the assigned port and forward them to the port of the voiceclient 101. Alternatively, the NAT (Network Address Translation) may beinformed of the public to private address mapping to perform propertranslation for incoming data packets.

FIG. 10 a and FIG. 10 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives aMDCX message from a call agent (step 1001) with the EndpointID being asingle endpoint (e.g., a voice line at the VPS). After receiving theMDCX message, the local voice client is retrieved from the line mappingtable according to the EndpointID specified in the MDCX command (step1002). The NotifiedEntity is saved (step 1003). The EndpointID parameteris replaced with the local voice client identifier and theNotifiedEntity is replaced with the address of the VPS 100 (step 1004).The MDCX command is then delivered to the local voice client (step1005). After receiving a response from the voice client with aLocalConnectionDescriptor parameter (step 1006), the voice proxy systemmodifies a previously saved public to private address mappinginformation for this connection (step 1007) so that the private IPaddress and port number will have the new specified value. The VPS setsup a new receiving port to forward voice/data packets to the voiceclient. Alternatively, the NAT Network Address Translation) may beinformed of the public to private address mapping to perform propertranslation for incoming data packets (not shown). The public IP addressand port number of the connection is retrieved (step 1008) and themodified response is sent to the restored NotifiedEntity (i.e., the callagent 105) using the public-known address in theLocalConnectionDescriptor (step 1009).

FIG. 11 a and FIG. 11 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives aDLCX command from a call agent with the EndpointID being a singleendpoint (step 1101). The Notified Entity, ConnectionID and CallID maybe specified. The local voice client is retrieved from the line mappingtable according to the EndpointID specified in the DLCX command (step1102). The NotifiedEntity parameter is saved and replaced with theaddress of the VPS 100 and the EndpointID parameter is replaced with thelocal voice client identifier (step 1103). The modified DLCX command isdelivered to the local voice client (step 1105) and the voice clientsends a response to the VPS 100 (step 1106). The CallID, ConnectionIDinformation and associated public to private address mapping informationis deleted (step 1107). The NAT may be requested to disable the addresstranslation (not shown) or the VPS will disable the translation if itwas performed by itself. The parameters associated with the connectionsuch as the ConnectionParameters are saved for performance measurements(step 1108). Finally, the response to the restored NotifiedEntity issent to the call agent (step 1109), the “restored NotifiedEntity”indicating the address of the call agent 105.

FIG. 12 a and FIG. 12 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives aDelete Multiple connection (DLXC) command with only CallID andEndpointID being specified (step 1201). The local voice clients areretrieved from the line mapping table according to the CallID andEndpointID specified in the DLCX command (step 1202). The VPS deliversthe DLCX command to each of the retrieved voice clients (step 1203).After all responses are received from the voice clients, the VPS deletesCallID information and all the associated public to private addressmapping information (step 1204) and sends one response back to the callagent (step 1205). The voice proxy system may need to request the NAT todisable all the associated address translations or it will stop all theaddress translations (not shown).

FIG. 13 a and FIG. 13 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives aDelete Multiple connection (DLXC) command with only EndpointID beingspecified. The VPS receives a DLCX message from a call agent (step 1301)with only EndpointID being specified, then retrieves all local voiceclients from the line mapping table according to the EndpointIDspecified in the DLCX command (step 1302). The VPS delivers the DLCXcommand to each of the retrieved voice clients (step 1303). After allresponses are received from the voice clients, the VPS deletes CallIDinformation, Connection ID information, and all the associated public toprivate address mapping information (step 1304) and sends one responseback to the call agent (step 1305). The VPS may also request the NAT todisable all the associated address translations or it will stop all theaddress translations (not shown).

FIG. 14 a and FIG. 14 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives aDelete Connection (DLCX) (step 1401) from a local voice client. Thecorresponding logical line number at VPS is retrieved (step 1402).ConnectionParameters are saved for performance measurements (step 1403).The callID information, ConnectionID information, and associated publicto private address mapping information are deleted (step 1404). VPS mayalso request the NAT to disable the address translation if necessary orit will stop the translation (not shown). EndpointID parameter isreplaced with a new identifier (step 1405) and the DLCX command isdelivered to the call agent (step 1406).

FIG. 15 a and FIG. 15 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives anAudit Endpoints command (AUEP) from a call agent (step 1501) withEndpointID specified as a single endpoint. RequestedInfo may also bespecified. The VPS retrieves the local voice client from the linemapping table according to the EndpointID specified in the AUEP command(step 1502). The EndpointID parameter is replaced with the local voiceclient identifier (step 1503) and the AUEP command is delivered to thelocal voice client (step 1504). After the VPS receives a response fromthe voice client, the VPS replaces the NotifiedEntity if presented witha previously stored value (step 1505) and sends the response to therestored NotifiedEntity (step 1506), corresponding to the call agent105.

FIG. 16 a and FIG. 16 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives anAudit Multiple Endpoints (AUEP) command with a wild card (e.g. =*@VPS).The VPS 100 retrieves all the local voice clients from the line mappingtable within the VPS 100 (step 1602). The VPS 100 sends the AUEP commandto each of the retrieved voice clients with the EndpointIDparameter=*@vc (step 1603). Once responses are received from the voiceclients, the VPS updates the line mapping table accordingly (step 1604).The VPS sends one response to the call agent when all responses from thevoice clients are received including a list of endpoints (step 1605).

FIG. 16 c illustrates another exemplary application of the VPS 100 ofthe present invention. In this example, the VPS receives an AUEP messagefrom a call agent with EndpointID=*@VPS and a parameter associated withthe maximum number of Endpoints such as the MaxEndPointIDs specified(step 1610). The VPS 100 retrieves all the local voice clients from theline mapping table (step 1611) and sends the AUEP command withEndpointID parameter=*@vc to each of the retrieved voice clients (step1612). Once responses are received from the voice clients, the VPSupdates the line mapping table accordingly (step 1613) and when all theresponses are received, the VPS may have N logical lines correspondingto the physical lines at the voice clients (step 1614). If N is lessthan or equal to MaxEndPointIDs, the VPS sends one response to the callagent with a list of N endpoints (step 1615). If not, the VPS sends oneresponse to the call agent including a list of endpoints, the number ofendpoints being equal to the value of MaxEndPointIDs, along with thetotal number of endpoints, NumEndPoints=N (step 1616).

FIG. 16 d illustrates another exemplary application of the VPS 100 ofthe present invention. In this example, the VPS receives an AUEP messagefrom a call agent with EndpointID=*@VPS and the MaxEndPointIDs and aparameter indicating a specified endpoint identifying parameter such asthe SpecificEndPointID are specified (step 1620). The VPS calculates thenumber of endpoints (“M”) after the SpecificEndPointID (step 1621). If Mis less than or equal to MaxEndPointIDs (step 1622), then the VPS sendsone response to the call agent with a list of M endpoints, the firstendpoint being the endpoint immediately following the SpecificEndPointID(step 1623)—i.e., the remaining list of endpoints. If M is greater thanMaxEndPointIDs, then the VPS sends one response to the call agent with alist of endpoints, the list containing a number of endpoints equal tothe value of MaxEndPointIDs and the first endpoint being the endpointimmediately following the SpecificEndPointID (step 1624)—i.e., the nextblock of endpoints. In this case, the VPS may also send the number ofthe total number of endpoints, N, as NumEndPoints.

FIG. 16 e illustrates another exemplary application of the VPS 100 ofthe present invention. In this example, the VPS receives an AUEP messagefrom a call agent with EndpointID=*@VPS and the SpecificEndPointID isspecified (step 1630). The VPS sends one response to the call agent witha list of endpoints (step 1631). The list of endpoints starts at a firstendpoint, the first endpoint being the endpoint immediately after theSpecificEndPointID. In this way, the VPS sends the remaining list ofendpoints.

FIG. 17 a and FIG. 17 b illustrate another exemplary application of theVPS 100 of the present invention. In this example, the VPS receives anAudit Connection command (AUCX) from a calling agent (step 1701) withEndpointID specified as a single endpoint. The voice client is retrievedfrom the line mapping table of the VPS according to the EndpointIDspecified in the AUCX command (step 1702). The EndpointID parameter isreplaced with the local voice client identifier (step 1703) and the AUCXcommand is delivered to the local voice client (step 1704). When the VPSreceives a response from the voice client, the VPS replaces theNotifiedEntity if presented with the previously stored value (step 1705,1706), modifies the LocalConnectionDescriptor if presented to have thecorresponding public-known media packet receiving IP address and portnumber (step 1707, 1708), saves the ConnectionParameters if presentedfor performance measurements (step 1709, 1710) and sends the response tothe restored NotifiedEntity (step 1711), which corresponds to the callagent 105.

It is understood that the present invention can take many forms andembodiments. The embodiments shown herein are intended to illustraterather than to limit the invention, it being appreciated that variationsmay be made without departing from the spirit of the scope of theinvention.

Although illustrative embodiments of the invention have been shown anddescribed, a wide range of modification, change and substitution isintended in the foregoing disclosure and in some instances some featuresof the present invention may be employed without a corresponding use ofthe other features. Accordingly, it is appropriate that the appendedclaims be construed broadly and in a manner consistent with the scope ofthe invention.

1. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) an Internet Protocol data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address; translating the destination address wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all endpoints; receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter, obtaining a plurality of endpoints corresponding to the first e endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter comprises an identifier for an obtained endpoint; and delivering the Internet Protocol data packet to a destination node on a second network based on said translating.
 2. The method of claim 1 wherein the Internet Protocol data packet carries Voice-over-IP (VoIP) protocol messages.
 3. The method of claim 2 wherein the Voice-over-IP (VoIP) protocol is one of Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol and Session Initiation Protocol (SIP).
 4. The method of claim 3 wherein the Voice-over-IP (VoIP) protocol is MGCP/NCS.
 5. The method of claim 4 wherein the VoIP protocol provides call control.
 6. The method of claim 1 wherein the first network is a public network and the second network is a private network, said private network comprising a plurality of local nodes.
 7. The method of claim 1 wherein the first network is a private network comprising a plurality of local nodes and the second network is a public network.
 8. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter corresponding to a private network node; checking a mapping table for the first endpoint identifying parameter; allocating a logical line number to create a VPS endpoint identifying parameter based on said checking, wherein the VPS endpoint identifying parameter comprises the logical line number and VPS IP address; saving a mapping of the first endpoint identifying parameter and the VPS endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with the VPS endpoint identifying parameter.
 9. The method of claim 8 wherein said translating further comprises: receiving a first parameter corresponding to a Call Agent of a public network; saving the first parameter; replacing the first parameter with a second parameter, the second parameter corresponding to the VPS.
 10. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter from a private network node, wherein the first endpoint identifying parameter represents a group of endpoints; querying the number of endpoints associated with the private network node; receiving a list of endpoint identifying parameters associated with the private network node; checking a mapping table for each of the endpoint identifying parameters associated with the private network node; obtaining a corresponding VPS endpoint identifying parameter for each of the endpoint identifying parameters associated with the private network node; and replacing each of the endpoint identifying parameters associated with the private network node with corresponding VPS endpoint identifying parameter, each of the VPS endpoint identifying parameters comprising a logical line number and VPS IP address.
 11. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter corresponding to a private network node; checking a mapping table for the first endpoint identifying parameter; and sending a NACK response based on said checking.
 12. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a VPS endpoint; checking a mapping table for the first endpoint identifying parameter; obtaining an identifier for a destination node in a private network from the mapping table, the identifier corresponding to the first endpoint identifying parameter; and replacing the first endpoint identifying parameter with a second endpoint identifying parameter, wherein the second endpoint identifying parameter identifies the destination node in the private network.
 13. The method of claim 12 wherein said translating further comprises: receiving a first parameter corresponding to a Call Agent of the public network; saving the first parameter; and replacing the first parameter with a second parameter, the second parameter corresponding to the VPS.
 14. The method of claim 12 further comprising: receiving a Transaction Identifier from a private network node; retrieving a corresponding endpoint from the mapping table based on the Transaction Identifier; receiving a parameter comprising a receiving address of the private network node, said receiving address of the private network node comprising a private IP address and port number; assigning a port number to create a public receiving address, said public receiving address comprising the VPS IP address and the assigned port number; mapping a connection between the receiving address of the private node and the public receiving address; and saving mapping information, said mapping information comprising the connection between the private receiving address and the public receiving address.
 15. The method of claim 14 further comprising modifying the mapping information.
 16. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing one of a plurality of endpoints; checking a mapping table for the first endpoint identifying parameter; obtaining an endpoint from the plurality of endpoints associated with the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a second endpoint identifying parameter, wherein the second endpoint identifying parameter identifies the obtained endpoint.
 17. The method of claim 16 wherein said translating further comprises: receiving a first parameter from a private network node, the first parameter indicating a notified entity corresponding to the VPS; and replacing the first parameter with a second parameter, wherein the second parameter corresponds to an address of a Call Agent in a public network.
 18. The method of claim 16 further comprising: receiving a Transaction Identifier from a private network node; retrieving a corresponding endpoint from the mapping table based on the Transaction Identifier; receiving a parameter from a private network node, said parameter comprising a receiving address of the private network node, said receiving address of the private network node comprising a private IP address and port number; and modifying previously stored mapping information, wherein the mapping information comprises the connection between the private receiving address and the public receiving address.
 19. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter, wherein the first endpoint identifying parameter comprises a wild card representing multiple endpoints; checking a mapping table for the first endpoint identifying parameter; obtaining a plurality of endpoints associated with the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter identifies a corresponding endpoint.
 20. The method of claim 19 further comprising: receiving a Transaction Identifier from a private network node; retrieving corresponding endpoints from the mapping table based on the Transaction Identifier; and deleting mapping information for the retrieved endpoints.
 21. The method of claim 1 wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all of the endpoints; checking a mapping table for the first endpoint identifying parameter; obtaining a plurality of endpoints corresponding to the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter identifies an obtained endpoint.
 22. The method of claim 21 further comprising: receiving a list of endpoint identifying parameters from each node in a private network; checking a mapping table for each of the endpoint identifying parameters received from each node in the private network; retrieving VPS endpoint identifying parameters corresponding to each of the endpoint identifying parameters received from each node in the private network from the mapping table; and replacing each of the endpoint identifying parameters received from each node in the private network with a corresponding VPS endpoint identifying parameter.
 23. The method of claim 1 further comprising: receiving a list of endpoint identifying parameters from each node in a private network, checking the mapping table for each of the endpoint identifying parameters received from each node in the private network; retrieving VPS endpoint identifying parameters corresponding to the endpoint identifying parameters received from each node in the private network from the mapping table; calculating the total number of retrieved VPS endpoint identifying parameters; and preparing a list of VPS endpoint identifying parameters comprising less than or equal to the maximum number of endpoint identifying parameters allowed to be returned.
 24. The method of claim 23 wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all endpoints; receiving a parameter corresponding to a specific endpoint identifying parameter; and preparing a list of VPS endpoint identifying parameters, wherein the first endpoint identifying parameter on the list of VPS endpoint identifying parameters is the endpoint identifying parameter immediately following the specific endpoint identifying parameter.
 25. The method of claim 23 wherein said translating comprises: receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all endpoints; receiving a parameter corresponding to a specific endpoint identifying parameter; receiving a parameter indicating the maximum number of endpoint identifying parameters to return; and preparing a list of VPS endpoint identifying parameters, wherein the first endpoint identifying parameter on the list of VPS endpoint identifying parameters is the endpoint identifying parameter immediately following the specific endpoint identifying parameter and wherein the number of VPS endpoint identifying parameters on the list of VPS endpoint identifying parameters is less than or equal to the maximum number of endpoint identifying parameters allowed to be returned.
 26. The method of claim 1 wherein said delivering comprises sending modified signaling messages from private network nodes to a Call Agent in a public network.
 27. The method of claim 1 wherein said delivering comprises sending modified signaling messages from a Call Agent in a public network to a desired private network node wherein the IP address of the private network node is retrieved from a mapping table.
 28. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter corresponding to a private network node receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; allocating a logical line number to create a VPS endpoint identifying parameter based on said checking, wherein the VPS endpoint identifying parameter comprises the logical line number and VPS IP address; saving a mapping of the first endpoint identifying parameter and the VPS endpoint identifying parameter in the mapping table; replacing the first endpoint identifying parameter with the VPS endpoint identifying parameter; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 29. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter from a private network node, wherein the first endpoint identifying parameter represents a group of endpoints; querying the number of endpoints associated with the private network node; receiving a list of endpoint identifying parameters associated with the private network node; checking a mapping table for each of the endpoint identifying parameters associated with the private network node; obtaining a corresponding VPS endpoint identifying parameter for each of the endpoint identifying parameters associated with the private network node; and replacing each of the endpoint identifying parameters associated with the private network node with corresponding VPS endpoint identifying parameter, each of the VPS endpoint identifying parameters comprising a logical line number and VPS IP address; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 30. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a VPS endpoint receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; obtaining an identifier for a destination node in a private network from the mapping table, the identifier corresponding to the first endpoint identifying parameter; and replacing the first endpoint identifying parameter with a second endpoint identifying parameter, wherein the second endpoint identifying parameter identifies the destination node in the private network; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 31. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing one of a plurality of endpoints receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; obtaining an endpoint from the plurality of endpoints associated with the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a second endpoint identifying parameter, wherein the second endpoint identifying parameter identifies the obtained endpoint; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 32. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter, wherein the first endpoint identifying parameter comprises a wild card representing multiple endpoints receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; obtaining a plurality of endpoints associated with the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter identifies a corresponding endpoint; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 33. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all of the endpoints receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; obtaining a plurality of endpoints corresponding to the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter identifies an obtained endpoint; and delivering the VoIP data packet to a destination node on a second network based on said translating.
 34. A method for managing network services between a plurality of networks comprising: receiving at a Voice Proxy Server (VPS) a Voice-over-Internet Protocol (VoIP) data packet with a corresponding address from a first network source, wherein the Internet Protocol data packet comprises a header and a payload and the payload of said Internet Protocol data packet contains at least a portion of a destination address and wherein the VoIP protocol is Media Gateway Controller Protocol (MGCP)/Network-based Call signaling (NCS) protocol; receiving a first endpoint identifying parameter from a public network, wherein the first endpoint identifying parameter comprises a wild card representing all endpoints; receiving a value indicating a maximum number of endpoints to return; checking a mapping table for the first endpoint identifying parameter; obtaining a plurality of endpoints corresponding to the first endpoint identifying parameter in the mapping table; and replacing the first endpoint identifying parameter with a plurality of second endpoint identifying parameters, wherein each second endpoint identifying parameter comprises an identifier for an obtained endpoint; and delivering the VoIP data packet to a destination node on a second network based on said translating. 